Semiconductor Device Clamping Word Lines During Standby Mode Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices fail to adequately prevent erroneous writes to memory cells during mode transitions between normal and standby modes due to noise generated by power supply voltage edges.
Innovation Solution
A semiconductor device with a control circuit that manages power supply voltages and switches to clamp word lines to a reference voltage during standby mode and reconnects them during normal mode, preventing noise from affecting memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power supply voltage is shut off during standby mode to reduce power consumption, then power consumption is reduced, but noise is generated during mode transition that can cause erroneous writes to memory cells
Solution Approach 1:
The control circuit activates the clamping circuit before shutting off the power supply voltage to Word Line Drivers. This preliminary action ensures that word lines are already clamped to a predetermined potential when power is cut, preventing noise-induced erroneous writes during the transition to standby mode.
Solution Approach 2:
The clamping circuit applies a counteracting effect by forcing word lines to a predetermined potential, which counteracts the harmful noise that would otherwise be generated during power supply transitions. This preliminary anti-action prevents the harmful effect before it can occur.
2Reliability
If word line drivers remain connected during standby mode to prevent noise, then data integrity is maintained, but power consumption increases due to gate leak current
Solution Approach 1:
The clamping circuit is activated in advance before power supply voltage is shut off. This ensures that when Word Line Drivers are disconnected and enter high impedance state, the word lines are already clamped to a stable potential, preventing noise effects even though the drivers are disconnected.
Solution Approach 2:
The system separates the functions of power supply control and word line potential control. The clamping circuit independently manages word line potential while Word Line Drivers can be disconnected for power savings, dividing the protection function from the power management function.
3Reliability
If clamping circuit is activated before power supply shutdown, then erroneous writes are prevented during mode transition, but device complexity increases
Solution Approach 1:
The clamping circuit serves multiple functions: it clamps word lines during standby mode transitions, prevents erroneous writes, and works in conjunction with the power supply control circuit. This multi-functionality reduces the need for separate dedicated circuits for each function.
Solution Approach 2:
The control circuit integrates the control of the clamping circuit activation with the power supply shutdown sequence. By merging these control functions, the system reduces overall complexity while achieving reliable noise prevention during mode transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents erroneous writes to memory cells by interrupting and reconnecting power supply to word line drivers during mode transitions, thereby isolating noise and maintaining data integrity.
Implementation Method 1
The plurality of first switches are provided to correspond to the plurality of word lines, respectively, and each is connected between a corresponding one of the word lines and a reference node providing a reference voltage
Implementation Method 2
The second switch is provided at a power supply line serving for supplying the second internal power supply voltage to the plurality of word line drivers
Data Source
AI summary
When an operational mode is shifted to a standby mode, a first transistor is brought into a conduction state by a control signal, and a word line is thereby clamped to a ground voltage. Further, a second transistor is brought into a non-conduction state, and supply of an internal power supply voltage to a word line driver is shut off. Subsequently, the supply of the internal power supply voltage is halted for saving electrical power. When the operational mode returns to a normal mode, the supply of the internal power supply voltage is started, and subsequently, the first transistor is brought into the non-conduction state by the control signal, and the second transistor is thereby brought into the conduction state.